Electric plug



April 7, 1942- R. Mc'cu'TcHEcN 2,279,173

f I vELEGTRIC PLUG Filed July 16, 1940 Patented Apr. 7, 1942 UNITED STATES PATENT OFFICE ELECTRIC PLUG.

Raymond McCutcheon, Chicago, Ill.

Application July 16, 1940, Serial No. 345,820

3` Claims.

My invention relates to electric plugs of the standard type employed in homes, offices, etc., for service from electric current outlets, and my main object is to provide a plug of this kind which can be attached to the cord or wiring without the use of screws or tools.

A further object of the invention is to prov-ide an electric plug in which the terminals of the contacting wires are securely clamped.

Another object of the invention is to construct the plug with two prong units which are rigidly secured and braced against dislodgment or deviation from their proper positions.

An additional object of the invention is to design the novel plug with few parts which are simple and substantial, so that the plug may be inexpensively manufactured and depended upon to serve efliciently for a long time.

With the above objects in view and any others which may suggest themselves from the description to follow, a better understanding of the invention may be had by reference to the accompanying drawing, in which- Fig. l is a vertical section of the plug;

Fig. 2 is a top plan View;

Fig. 3 is a group perspective oi one ofthe terminal units; l

Fig. 4 is a View similar to Fig, 5, showing a modification;

Fig. 5 is a perspective view showing a prong unit employed in the modiiication;

Fig. 6 is a section of a brace taken on the line 6 6 of Fig. 4; and

Fig. 7 is a bottom plan view of a portion of Fig. 6.

The attachment and use of electric plugs in homes, ofdces, etc., has in late yearsv become familiar to the average mechanically inclined person, and it is a common occurrence for such persons to attach new plugs to electric light cords or replace defective plugs. In such cases, a screw-driver--and sometimes a pair of pliersis needed to do the job. Also, the rough handling or the application of these tools when a. plug repair or installation is made often loosens one of the terminals from the base to which it is attached by screws, rivets or eyelets. Often, the screws employed for the attachment of the wires often become jammed, making it difficult to release them; or, they become loose from the handling of the cord or appliance, so that the electrical contact or connection is impaired. It has therefore been my intention to depart from the deficiencies outlined above and provide a plug which contains no screws, rivets or eyelets, and

requires no tools for its installation or removal, so that even persons having no mechanical knowledge may easil-yr learn to apply, repair or changea plug connection.

In accordance with the foregoing, speci-o reference to the drawing indicates a typical electric service cord at I0, and the current wires' issuing therefrom at II. The novel electric plug I2 has a body or casing similar to the conventional types of plugs, such casing having an opening I3 in the bottom for the entrance of the cord I0. The Afamiliar type of metal prongs I4' extends from the casing in a manner to fit standard current outlets.

For the purpose of the present invention, each prong I4 is made with any integral segmental base I5 which is suitably attached or embedded in the stock Ilia of the plug casing, whereby tov permanently secure the same to the casing. Itis understood that a pair of the rprong units I4 is deposited in the casing in opposed relation, as suggested in Fig. 2, and amply spaced for the free approach or manipulation of the current wires II for purposes of attachment.

In the main embodiment-of the plug, the base I5 of the prong unit is formed with a doubled arch I6 at one side of the prong, such arch havinga transverse opening I'I. The arch is intended to receive a sheet metal cap I8 which is adapted to fit over the arch and become tensioned as tted, so as to snugly engage the arch. One side of the cap I8 is made with a bottom notch I9; and the material in the region of the notch is expanded to form an arched channel ZIJ in the center of the cap, such channel opening on the notch I9 at one end and extending to the bottom of the cap with the other end.

In the application of one of the current wires to the prong unit I4, it is customary to train the wire around the back of the prong, as shown in Figs. 1 and 2. The stripped terminal portion of the wire is now passed through the opening I'I in the arch I6, then trained upwardly to return over the arch and descend over the initial portion. Now the cap I8 is applied with downward pressure, so that when the cap has been fully depressed. to seat on the base I5 or close thereto, the initial portion of the stripped wire is found to have passed through the notch I9 and taken a looped course in the channel 20 to return and issue upon itself. Thus, the cap I8 not only forms a clamp to retain the stripped Wire to the arch I6, but provides a clearance by Way of the notch I9 and the channel 20 for the wire, so that the latter is individually clamped and retained in place, this clamping and retention not impairing the snug and uniform t of the cap I8 upon the arch I6. Thus, with these parts properly designed, a tight t of the connection is attained, all without the use of any screws or tools.

In order that the alinement of the prongs I4 may be insured, I provide a block 2| of insulation material as a brace therefor. Thus, the block is made with two narrow vertical slots 22 for the slidablefpassage of the prongs I4, and the ends of the blockare suitably sealed or pressed into the casing I2 so as to become rigidly attached thereto.

In the modication, the prong unit I4 is made without the arch I6, but uses the bracing block for the clamping of the wires. Thus, Figs, `4 and 5 show that the prong I4 is made with two vertically spaced openings 23 in the middle, and` that the stripped wire II is looped through these. The bracing block 24 is in this'instance made detachable and its vertical slots 25 are enlarged along the middle with opposed vertical channels 26 which commence a short distance from the top, as shown in Fig. 6. Thus, when the block is applied over the prongs I4 and slid down along the same, the looped wires II in the region of the openings 23 will be received in the opposed channels 26. It is understood that the t ofthe slots 25 on the prongs and thechannels 26 on the wires will be fairly tight in the present instance, in order to impart the action of a clamp to firmly press the Wires to the prongs; and the endwise t of the block 25 in thewalls of thel plug casing 2l) will also he fairly tight, in order that the block may hold its place during the handling or use of the plug. Of course, itfollows that the plug will be removable by hand with a limited amount of exertion in case a repair or replacement must be made.

It will be evident from the above description that I have provided an electric plug which is inexpensive to produce .because of the elimination of screws, tapped receptacles therefor and other instrumentalities employed in plugs now on the market. It is simplyl necessary `to firmly attach the prong units in the casing of the plug at the factory, this also applying tothe bracing block 2I in the main embodimentfof4 the plug.

Only one further part is required for the main form, this being a cap I8. As to the handling of the plug for application, repair or replacement, very little instruction is necessary to make the same familiar to the average person, so that these tasks can be accomplished readily as needed, without tools, and without calling a trained or mechanically inclined person for aid. The novel plug is thus an article which is simplified in construction and easily serviced by any person.

While I have described the'main and modified forms of the invention along specific lines, various `minor changes and renements may be made without departing from their principle, and I desire to consider all such changes and refinements as coming within the scope and spirit of the appendedclaims.

` I claim:

1. In an electric plug having a body of insulating material provided with a circuit wire passage, a terminal comprising a base flange secured in the plug body, a contact prong extending therefrom, said iiange having a portion doubled upon itself at a point spaced from the prong and apertured to receive a circuit wire therethrough, and a metal cap detachably engageable over said doubledv portion to confine therebeneath a Wire when trained through and over said doubled portion.

42. The structure of claim l, and said cap beinginternally channelled to engage over the wire in frictional binding contact with said doubled portion. f

. 3. In an electric plug, a body provided with a circuit wirepassage, a terminal comprising a base lflange, secured in the plug body, a retainer block ofinsulating material; securedin the plug body over said flange, a contact prong extending from said flangethrough said block, said ange having aV-portion doubled uponitself at one side of the block ancl apertured toreceive a contact wire therethrough, anda metal cap engageable over said doubled portion to 4confine thereunder and clamp against said portion a circuit wire trained through its aperture, said cap being of a length not greater than the thickness of said insulating block. c

RAYMOND MCCUTCHEON. 

